306 LAND SCULPTURE 



action will have will depend largely upon the character and 

 arrangement of the rocks which make up the coast, and whether 

 the shore rises steeply or gently out of the sea. The first effect 

 of the wearing action of the sea is to increase the irregularity of 

 the coast-line, by taking advantage of the weaker spots, with 

 headlands and rocky points formed of the more resistant portions 

 (see Fig. 42). Eventually, however, the headlands are cut back, 

 leaving a submarine platform to mark their former extension, 

 while from this platform may rise islets of erosion, formed by 

 masses of rocks which have better resisted the assaults of the 

 waves. In areas of deposition bars, shoals, and sand spits are 

 thrown up by the winds and waves, running parallel with the coast, 

 and the open beaches take on a crescentic form. Long-continued 

 action of the sea at a constant level thus tends to approximate the 

 even and regular coast-lines of the newly upheaved land. However, 

 an inspection of the structure of the coast will reveal the difference. 



A coast which has been depressed within a comparatively 

 recent period is one of marked irregularity of outline. The ad- 

 vancing sea fills all the lower valleys, while the higher ridges stand 

 out as headlands and promontories. Isolated hills and mountains 

 are separated from the mainland and converted into islands. The 

 rivers are drowned, their lower courses converted into estuaries, 

 into which side streams empty separately, that before had joined 

 the main stream. A very irregular coast-line, penetrated by many 

 estuaries, inlets, or fjords, and fringed with numerous islands, indi- 

 cates the submergence of a region already carved into strong relief 

 by the subaerial agencies. Such a coast is admirably typified by 

 that of Maine, where the topography was evidently modelled by 

 subaerial denudation, while a comparatively recent depression has 

 brought the sea over it. The actual form taken by a lowered 

 coast will depend upon the degree and character of the relief 

 which had been attained before the depression, and upon the 

 amount of the subsidence. 



The depression of a low- lying coast of small relief is made mani- 

 fest chiefly in the invasion of the rivers by tidal waters and their 

 conversion into estuaries, examples of which are New York, Dela- 



